Pediatric Nephrology
Pediatr Nephrol (1992) 6 : 4 1 2 - 4 1 6 9 IPNA 1992
Original article Prognosis of patients with unilateral renal agenesis Luis R. Arguesol, Michael L. Ritchey 1, Emmett T. Boyle, Jr.2, Dawn S. Milliner3, Erik J. Bergstralh4, and Stephen A. Kramerl 1 Department of Urology, 3 Division of Nephrology and Internal Medicine and Section of General Pediatrics and Pediatric Nephrology, and 4 Section of Biostatistics, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, USA 2 Section of Urology, Mayo Clinic Scottsdale, Scottsdale, Arizona, USA Received August 1, 1991; received in revised form December 27, 1991; accepted March 6, 1992
Abstract. The clinical course was reviewed in 157 patients with unilateral renal agenesis and a normal contralateral kidney for the purpose of establishing a prognosis. There were 85 males (54%) and 72 females (46%). The mean age at diagnosis of unilateral renal agenesis was 37 years. The mean years at risk was 56. Proteinuria (>150 mg/24 h) was found in 19% of the 37 patients tested (P 0.10 NA, Not applicable a Of 6 patients who died of renal failure, 4 had renal symptoms at the time of diagnosis b Value includes 6 patients who died of renal failure c Same as years at risk Nineteen Patients (12%) chose not to participate in the study. Ninety-five patients (6i%) responded to a detailed medical questionnaire. Measurements of 24-h creatinine clearance, 24-h urinary protein excretion, and blood pressure were obtained for 38 of the 114 surviving patients (33%). The adequacy of urine collection was assessed by total creatinine excretion adjusted for body weight [12]. Thirteen patients underwent study in our renal function laboratory. Glomerular filtration rate (GFR) was measured by inulin clearance, effective renal plasma flow was assessed by para-aminohippuric acid (PAH) clearance, and the filtration fraction was calculated. The statistical comparison between groups was made using the chisquared or rank sum test as appropriate. A one-sample chi-squared test was used to compare the percentage of patients with proteinuria, renal insufficiency, or hypertension with the expected percentage based on published reference limits [12, 13]. Survival from the day of URA diagnosis to death was estimated using the Kaplan-Meier method [14]. Expected survival was estimated using United States life tables for patients of matched sex, age, and year of birth. There were 85 male patients (54%) and 72 (46%) female. The mean age at diagnosis of renal agenesis was 37 years (range 1-78 years). Females were diagnosed at an earlier mean age than males (32.9 vs 41.0 years, P = 0.015). The median follow-up after diagnosis was 19.1 years. The mean years at risk was 57. The left kidney was absent in 54% of the patients and the right kidney was absent in 46%. The diagnosis of URA was based on radiographic evaluation, including excretory urography, renal ultrasonography, computed tomography, or radioisotopic renal scans. URA was detected incidentally in 52% of patients during a general medical examination, and in 48% during evaluation of
various urological complaints, such as nonfebrile urinary tract infections, microscopic hematuria, or flank pain.
Results The m e d i c a l history profile was similar in the group with f o l l o w - u p l a b o r a t o r y data (n -- 38) and the group without l a b o r a t o r y data (n = 119) (Table 1). U r o l o g i c a l s y m p t o m s led to the diagnosis o f U R A m o r e frequently a m o n g patients without l a b o r a t o r y data than in those with laboratory data. H y p e r t e n s i o n and "other m e d i c a l p r o b l e m s " were r e p o r t e d m o r e frequently a m o n g those with laboratory data. U r i n a r y tract infections were reported b y 25% o f the patients who r e s p o n d e d to the questionnaire, h e m a t u r i a was r e p o r t e d in 8%, diabetes mellitus in 5%, and renal calculi in 5%.
Proteinuria M e a s u r e m e n t s o f 24-h urinary protein excretion were perf o r m e d in 37 patients. Proteinuria was defined as excretion o f m o r e than 150 mg/24 h. Proteinuria was found in 19% o f these patients (n = 7) c o m p a r e d with the 2.5% expected (P 150 mg/24 h b Patients were considered hypertensive if their systolic blood pressure was ~>160 mmHg, if their diastolic blood pressure was />95 mmHg, or if they were receiving medical treatment for hypertension Defined as having a creatinine clearance below published age- and sex-specific lower limits
Table 4. Serum creatinine and creatinine clearance in patients with and without renal insufficiency
Mean age at assessment (years) Mean serum creatinine (mg/dl)
Renal insufficiency (n = 4)
No renal insufficiency (n = 28)
72
56
1.55
1.05
Mean creatinine clearance (ml/min per 1.73 m 2)
42
88
Mean years at risk
72
56
Survival A t t h e t i m e o f t h i s r e p o r t , 1 1 4 p a t i e n t s ( 7 3 % ) w e r e alive. Forty-three patients (27%) had died; 6 deaths were caused by renal failure. In our study population, survival from the day of URA diagnosis was similar to expected survival a d j u s t e d fox" age, sex, a n d y e a r o f b i r t h (Fig. 1).
415 100 %
Expected
90
Observed ~ "
.............. (121)
(D
~ - ~ ......
8O
Pediatr Nephrol (1992) 6 : 4 1 2 - 4 1 6 9 IPNA 1992
Original article Prognosis of patients with unilateral renal agenesis Luis R. Arguesol, Michael L. Ritchey 1, Emmett T. Boyle, Jr.2, Dawn S. Milliner3, Erik J. Bergstralh4, and Stephen A. Kramerl 1 Department of Urology, 3 Division of Nephrology and Internal Medicine and Section of General Pediatrics and Pediatric Nephrology, and 4 Section of Biostatistics, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, USA 2 Section of Urology, Mayo Clinic Scottsdale, Scottsdale, Arizona, USA Received August 1, 1991; received in revised form December 27, 1991; accepted March 6, 1992
Abstract. The clinical course was reviewed in 157 patients with unilateral renal agenesis and a normal contralateral kidney for the purpose of establishing a prognosis. There were 85 males (54%) and 72 females (46%). The mean age at diagnosis of unilateral renal agenesis was 37 years. The mean years at risk was 56. Proteinuria (>150 mg/24 h) was found in 19% of the 37 patients tested (P 0.10 NA, Not applicable a Of 6 patients who died of renal failure, 4 had renal symptoms at the time of diagnosis b Value includes 6 patients who died of renal failure c Same as years at risk Nineteen Patients (12%) chose not to participate in the study. Ninety-five patients (6i%) responded to a detailed medical questionnaire. Measurements of 24-h creatinine clearance, 24-h urinary protein excretion, and blood pressure were obtained for 38 of the 114 surviving patients (33%). The adequacy of urine collection was assessed by total creatinine excretion adjusted for body weight [12]. Thirteen patients underwent study in our renal function laboratory. Glomerular filtration rate (GFR) was measured by inulin clearance, effective renal plasma flow was assessed by para-aminohippuric acid (PAH) clearance, and the filtration fraction was calculated. The statistical comparison between groups was made using the chisquared or rank sum test as appropriate. A one-sample chi-squared test was used to compare the percentage of patients with proteinuria, renal insufficiency, or hypertension with the expected percentage based on published reference limits [12, 13]. Survival from the day of URA diagnosis to death was estimated using the Kaplan-Meier method [14]. Expected survival was estimated using United States life tables for patients of matched sex, age, and year of birth. There were 85 male patients (54%) and 72 (46%) female. The mean age at diagnosis of renal agenesis was 37 years (range 1-78 years). Females were diagnosed at an earlier mean age than males (32.9 vs 41.0 years, P = 0.015). The median follow-up after diagnosis was 19.1 years. The mean years at risk was 57. The left kidney was absent in 54% of the patients and the right kidney was absent in 46%. The diagnosis of URA was based on radiographic evaluation, including excretory urography, renal ultrasonography, computed tomography, or radioisotopic renal scans. URA was detected incidentally in 52% of patients during a general medical examination, and in 48% during evaluation of
various urological complaints, such as nonfebrile urinary tract infections, microscopic hematuria, or flank pain.
Results The m e d i c a l history profile was similar in the group with f o l l o w - u p l a b o r a t o r y data (n -- 38) and the group without l a b o r a t o r y data (n = 119) (Table 1). U r o l o g i c a l s y m p t o m s led to the diagnosis o f U R A m o r e frequently a m o n g patients without l a b o r a t o r y data than in those with laboratory data. H y p e r t e n s i o n and "other m e d i c a l p r o b l e m s " were r e p o r t e d m o r e frequently a m o n g those with laboratory data. U r i n a r y tract infections were reported b y 25% o f the patients who r e s p o n d e d to the questionnaire, h e m a t u r i a was r e p o r t e d in 8%, diabetes mellitus in 5%, and renal calculi in 5%.
Proteinuria M e a s u r e m e n t s o f 24-h urinary protein excretion were perf o r m e d in 37 patients. Proteinuria was defined as excretion o f m o r e than 150 mg/24 h. Proteinuria was found in 19% o f these patients (n = 7) c o m p a r e d with the 2.5% expected (P 150 mg/24 h b Patients were considered hypertensive if their systolic blood pressure was ~>160 mmHg, if their diastolic blood pressure was />95 mmHg, or if they were receiving medical treatment for hypertension Defined as having a creatinine clearance below published age- and sex-specific lower limits
Table 4. Serum creatinine and creatinine clearance in patients with and without renal insufficiency
Mean age at assessment (years) Mean serum creatinine (mg/dl)
Renal insufficiency (n = 4)
No renal insufficiency (n = 28)
72
56
1.55
1.05
Mean creatinine clearance (ml/min per 1.73 m 2)
42
88
Mean years at risk
72
56
Survival A t t h e t i m e o f t h i s r e p o r t , 1 1 4 p a t i e n t s ( 7 3 % ) w e r e alive. Forty-three patients (27%) had died; 6 deaths were caused by renal failure. In our study population, survival from the day of URA diagnosis was similar to expected survival a d j u s t e d fox" age, sex, a n d y e a r o f b i r t h (Fig. 1).
415 100 %
Expected
90
Observed ~ "
.............. (121)
(D
~ - ~ ......
8O
